Monday, December 03, 2007

Here's a story that deserves a wider circulation. Former spook In From The Cold picked up on a piece in the Houston Chronicle about an apparent increase in the number, and a decrease in the strength, of tropical storms that are being given names (emphasis added):

Some meteorologists, including former hurricane center director Neil Frank, say as many as six of this year's 14 named tropical systems might have failed in earlier decades to earn "named storm" status.

"They seem to be naming storms a lot more than they used to," said Frank, who directed the hurricane center from 1974 to 1987 and is now chief meteorologist for KHOU-TV. "This year, I would put at least four storms in a very questionable category, and maybe even six."

Most of the storms in question briefly had tropical storm-force winds of at least 39 mph. But their central pressure — another measure of intensity — suggested they actually remained depressions or were non-tropical systems.

Any inconsistencies in the naming of tropical storms and hurricanes have significance far beyond semantics.

The number of a season's named storms forms the foundation of historical records used to determine trends in hurricane activity.

As In From The Cold notes:

hurricane forecasts for 2007 missed the mark badly; if the six "suspect" storms are excluded from the total, then there were only 8 hurricanes and tropical storms in the Atlantic basin this year. That's below the historical average for the past 60 years (10 storms a year) and barely half the original prediction for 2007 (17 named storms).

So alleged increases in storm frequency might be the result of changes to the criteria by which storms are assessed rather than global warming, as is often alleged.